| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a brushless motor that reduces variations in rotating speed of a rotor. <P>SOLUTION: A brushless motor 1 includes a baseplate 40 and a rotor 10. The rotor 10 is arranged for rotation relative to the baseplate 40, and has a first, annular magnetic portion magnetized in a plurality of poles, and a second, annular magnetic portion magnetized in a plurality of poles at an end face of the first magnetic portion facing the baseplate 40. The baseplate 40 is provided with a Hall element 41 for detecting a rotational position of the rotor 10 in the effect of the magnetic poles of the first magnetic portion, and an FG pattern 42 for detecting a rotating speed of the rotor 40 in the effect of the magnetic poles of the second magnetic portion. The magnetic flux that the Hall element 41 receives from the second magnetic portion is made lower than the magnetic flux that the Hall element 41 receives from the first magnetic portion enough to reduce variations in rotating speed of the rotor 10. <P>COPYRIGHT: (C)2012,JPO&INPIT |
